aurora/Aurora/Design/Views/BaseViewModel.cs

using System;
using System.ComponentModel;
using System.Runtime.CompilerServices;
using System.Threading.Tasks;
using Aurora.Models.Media;
using Xamarin.Forms;

namespace Aurora.Design.Views
{
    public class BaseViewModel : INotifyPropertyChanged
    {
        public BaseViewModel()
        {
        }

        #region Player 
        public virtual void PlayExecute()
        {

        }
        public virtual bool PlayCanExecute()
        {
            return true;
        }

        public virtual void NextExecute()
        {

        }
        public virtual bool NextCanExecute()
        {
            return true;
        }

        public virtual void PreviousExecute()
        {

        }
        public virtual bool PreviousCanExecute()
        {
            return true;
        }

        public BaseMedia Media { get; set; }

        #endregion Player

        #region Lifecycle
        public virtual void OnActive() { }

        public virtual void OnInactive() { }

        #endregion

        #region INotifyPropertyChanged Implementation
        public bool SetProperty<T>(ref T storage, T value, [CallerMemberName] string propertyName = null)
        {
            if (Object.Equals(storage, value))
                return false;

            storage = value;
            OnPropertyChanged(propertyName);
            return true;
        }

        public event PropertyChangedEventHandler PropertyChanged;
        public void OnPropertyChanged([CallerMemberName] string propertyName = "")
        {
            if (PropertyChanged == null)
                return;

            PropertyChanged.Invoke(this, new PropertyChangedEventArgs(propertyName));
        }
        #endregion
    }
}